1. Technical Field of the Invention
This invention relates to an electric power converter that has a semiconductor module having an integral semiconductor element and a capacitor connected to the semiconductor module.
2. Description of the Related Art
Electric power converters such as an inverter and a converter convert electric power by switching operation of a plurality of semiconductor elements.
In such an electric power converter, a capacitor that smoothes the current supplied to a semiconductor module from a direct-current power supply is electrically connected to the semiconductor module.
The electric power converter having the capacitor and the semiconductor module being connected via a bus bar is disclosed in Japanese Patent Application Laid-Open Publication No. 3646049.
However, the heat that is generated in the semiconductor module will be transferred to the capacitor through a terminal area and the bus bar in the conventional electric power converter mentioned above.
Thereby, there is a possibility that the temperature of the capacitor may become high and the capacitor may be deteriorated.
In particular, when the controlled current of the electric power converter has a high current density, the heat generation of the semiconductor module tends to become large.
In addition, with a raise in a heat resistance of the semiconductor element, the semiconductor element tends to be used at higher temperature.
Under this situation, even if the heat resistance of the semiconductor module is fully secured, the present condition is that the heat resistance of the capacitor is not fully secured.
Therefore, degradation of the capacitor by heat received from the semiconductor module in the electric power converter is an important subject in recent years.